Thanks for the comment!
I asked some people to play-test our game and responses were quite varied. Some people thought the game was unbeatable (including my partner); but some people told us that they could beat the entire game without much effort at all (I thought the game was easy). In the end, I did end up increasing the enemies' detection range and health. But in hindsight, I can see how you're right. Thanks again for the specific feedback!